Restaurant Kettle Explodes


Inside a restaurant kitchen, this 25-gallon
steam jacketed kettle became a bomb. The resulting blast injured three workers and destroyed
the large kitchen. I’m Nigel Corduff, Investigations Officer with WorkSafeBC. Restaurants use steam kettles like this one
to cook large volumes of soups, stews, and pasta. A steam kettle is essentially a pot with a
sealed, double-walled jacket. Inside the jacket are electric heating elements along with a
liquid. The elements heat the liquid inside the jacket,
turning it into super-heated water vapour. The heat from the water vapour is transferred
through the metal wall of the pot to the ingredients inside the kettle. The kettle that exploded had been in service
in the restaurant for many years. Prior to the explosion, the kettle had been malfunctioning.
It produced either high heat or no heat. An electrical contractor who was not a specialist
in this type of kettle attempted repairs, but ran into difficulties. Rather than removing
the kettle from service, as a temporary fix he connected the heating coils directly to
the on/off switch. In doing so, he bypassed several safety devices
of the kettle, including the electronic controls that regulate temperature and automatically
shut off the kettle in case of overheating. After the electrician left, a sous-chef, who
was not aware that the normal controls had been bypassed, turned the kettle on. He placed
sliced onions in the pot to sauté in preparation for a batch of soup. With the onions sautéeing,
he stepped away. Without any control to break the heating cycle,
the kettle started to overheat. The pressure inside the steam jacket went higher and higher,
pressing against its walls. There was one more safety device that could
protect against too much pressure, the kettle’s mechanical pressure relief valve. But the
valve had not been maintained – it was plugged and didn’t work. 20 minutes later, the kettle’s stainless
steel jacket couldn’t withstand the pressure any more – the kettle exploded. Hot steam
burst out and jagged kettle parts flew through air, damaging the kitchen and injuring the
sous-chef and two other workers. There are four key lessons to be learned here: Use qualified service technicians for the
repair of steam kettles. The electrician was not trained to repair this type of kettle. Regularly inspect and maintain steam jacketed
kettles and other pressure devices. The manufacturer’s inspection and testing schedule for the kettle
wasn’t followed. The kettle’s mechanical pressure relief valve, designed to prevent
this type of explosion, failed. It had not been checked every six months as required
by the manufacturer. Remove malfunctioning equipment from service. And never bypass safeguards. If you do, a
recipe for soup can become a recipe for disaster.

16 thoughts on “Restaurant Kettle Explodes

  1. the only 2 thinks i can think that the person that hired someone eather wanted to save money on fixing it or he did not want to spend money to get a new one

  2. Yeah, now EVERYBODY gets to pay for the kitchen workers' injuries because of a cheap manager and an idiotic electrician. There's a rosy future for us all.

  3. Thanks for posting this. I just bought a used steam kettle and was wondering about safety features and possible risks. I will definitely check with electricians that they are familiar with the safety features while they install.

  4. I make these things for a living it wouldn't have been that expensive of a fix the safety valve is most important part of that machine you think you was least check it to make sure it's working right

  5. #1 Always have a qualified person check the pressure relief valve for proper operation. If there is ANY Doubt this valve is faulty (leaking by or stiff operation) replace it with a new valve of proper pressure as per the manufacturers specifications.

    #2 Before operating with the kettle cold make sure kettle water level sight tube is at the proper level if there is no sight tube make sure the low water indicator lamp is not lit. It is also very important to check the pressure gauge to make sure it is in the negative pressure range while cold usually green to assure the proper vacuum is in the kettle jacket so the kettle will not overpressurize during the cooking cycle. If not negative or green on the gauge kettle water level must be checked and jacket must be purged. Turn the kettle on at a low temperature setting and listen and watch to make sure the kettle is cycling on / off in the proper manner. Always use the kettle with temperatue set at lowest range possible for your cooking needs. Never cook / simmer at a higher temperature than needed. Some kettle manufacturers recommend 3-6 ozs. of a product like NAPA Mac 1300 antirust mixed in with the kettle jacket water. (Check with manufacturer about adding this product to your kettle.) Hope this will help you operate your kettle safely!

  6. Same age old screw up: The electrician defeated all the safety devices then left without telling anyone to run the kettle of and on to keep it from exploding. That electrician needs his ass handex to him.

  7. a malfunction did not turn this into a bomb the electrician did by bypassing the electronic thermometer that regulates temperature and cuts off the power to the coils

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